Although many "molecular biologist" may regard "metabolic regulation" as a solved problem, the field is far from dead, and in fact appears to be entering into a new an exciting phase. The field has matured from a descriptive science to one capable of integrating biochemical relationships and mechanisms in dynamic terms--approaching the complexity of living cells. Kinetic models with demonstrated predictive value have been made: the ultimate test of their usefulness and general validity. In the past, progress in biochemistry has been achieved primarily through the isolation and in-depth analysis of individual cellular components. Progress in the future may well depend upon the extent to which this wealth of information can be used in dynamic models which simulate metabolism in intact cells and organisms. Only when the reductionistic and holistic approaches converge, will we really begin to understand the complexities of metabolism in vivo. Despite the fundamental importance of the dynamic analysis of metabolic processes, the field today is diffuse and confused in the minds of most biochemists. Too many arbitrary and useless models fill the literature. Given enough assumptions, any metabolic system can be modeled, yet not necessarily reflect metabolism in vivo. The greater the volume of experimental data with which a model is consistent and by which it is challenged, the greater the probability that it describes reality and approaches a unique solution. A primary objective of this conference is to establish ground rules for the construction and use of various kinds of metabolic models. The proposed program will consist of symposia and poster sessions. Funds are requested for the travel of 40 invited speakers and convenors from the international research community to address various aspects of metabolic modelling, and for 20 or so young investigators (graduate students and postdoctoral associates) giving poster presentations. These latter funds would be awarded competitively to young investigators from United States institutions.